#include <stdbool.h>
#include <stdlib.h>
#include <stdint.h>
#include <limits.h>
#include <string.h>
#include <assert.h>

#include "any_log.h"
#include "config.h"
#include "util.h"
#include "block.h"
#include "action.h"

#define ANY_INI_IMPLEMENT
#include "any_ini.h"

typedef enum {
    CONFIG_SUCCESS,
    CONFIG_INVALID,
    CONFIG_UNKNOWN,
} config_status_t;

static const config_entry_t bar_entries[] = {
    { "width",             CONFIG_UINT,     NULL, offsetof(config_t, width) },
    { "height",            CONFIG_UINT,     NULL, offsetof(config_t, height) },
    { "font",              CONFIG_STRING,   NULL, offsetof(config_t, font) },
    { "monitor",           CONFIG_STRING,   NULL, offsetof(config_t, monitor) },
    { "override-redirect", CONFIG_BOOL,     NULL, offsetof(config_t, override_redirect) },
    { "background",        CONFIG_GRADIENT, NULL, offsetof(config_t, background) },
    { "scale",             CONFIG_DOUBLE,   NULL, offsetof(config_t, scale) },
    { 0 },
};

static const config_entry_t block_entries[] = {
    { "hidden",     CONFIG_BOOL,     NULL, offsetof(block_t, hidden) },
    { "color",      CONFIG_GRADIENT, NULL, offsetof(block_t, bg_color) },
    { "line-color", CONFIG_GRADIENT, NULL, offsetof(block_t, line_color) },
    { "line-width", CONFIG_UINT,     NULL, offsetof(block_t, line_width) },
    { "x-padding",  CONFIG_UINT,     NULL, offsetof(block_t, x_padding) },
    { "y-padding",  CONFIG_UINT,     NULL, offsetof(block_t, y_padding) },
    { "min-width",  CONFIG_UINT,     NULL, offsetof(block_t, min_width) },
    { "max-width",  CONFIG_UINT,     NULL, offsetof(block_t, max_width) },
    { "interval",   CONFIG_TIME,     NULL, offsetof(block_t, update_interval) },
    { 0 },
};

static const config_entry_t block_group_entries[] = {
    { "spacing",  CONFIG_UINT, NULL, offsetof(block_group_t, spacing) },
    { "blocks",   CONFIG_LIST, NULL, offsetof(block_group_t, children) },
    { "collapse", CONFIG_BOOL, NULL, offsetof(block_group_t, collapse) },
    { 0 },
};

static config_enum_t text_align_enum[] = {
    { "left",   ALIGN_LEFT },
    { "center", ALIGN_CENTER },
    { "right",  ALIGN_RIGHT },
    { 0 },
};

static const config_entry_t block_text_entries[] = {
    { "text",       CONFIG_STRING, NULL,            offsetof(block_text_t, text) },
    { "text-color", CONFIG_COLOR,  NULL,            offsetof(block_text_t, text_color) },
    { "text-size",  CONFIG_UINT,   NULL,            offsetof(block_text_t, text_size) },
    { "text-align", CONFIG_ENUM,   text_align_enum, offsetof(block_text_t, text_size) },
    { 0 },
};

static bool config_read_string(const char *value, char **result)
{
    if (value == NULL)
        value = "";

    size_t start = 0, end = strlen(value);
    if (value[0] == '"' && value[end - 1] == '"') {
        start++;
        end--;
    }

    free(*result);
    *result = strslice(value, start, end);
    return true;
}

static bool config_read_int(const char *value, int *result)
{
    char *end;
    long n = strtol(value, &end, 0);
    *result = n;

    if (n > INT_MAX || n < INT_MIN)
        log_debug("Integer %ld is out of range", n);

    return *end == '\0' && n != LONG_MIN && n != LONG_MAX;
}

static bool config_read_uint(const char *value, unsigned int *result)
{
    char *end;
    unsigned long n = strtoul(value, &end, 0);
    *result = n;

    if (n > UINT_MAX)
        log_debug("Integer %lu is out of range", n);

    return *end == '\0' && n != ULONG_MAX;
}

static bool config_read_double(const char *value, double *result)
{
    char *end;
    *result = strtod(value, &end);
    return *end == '\0';
}

static bool config_read_bool(const char *value, bool *result)
{
    if (!strcmp(value, "false")) {
        *result = false;
        return true;
    }

    if (!strcmp(value, "true")) {
        *result = true;
        return true;
    }

    log_debug("Invalid bool value");
    return false;
}

static bool config_read_color(const char *value, color_t *result)
{
    if (value[0] == '#') {
        char *end;
        unsigned long n = strtoul(value + 1, &end, 16);

        if (end[0] != '\0')
            return false;

        int bpc = 0;
        switch (end - (value + 1)) {
                case 3:
                    bpc = 4;
                    n = (n << 4) | 0x0f;
                    break;

                case 6:
                    bpc = 8;
                    n = (n << 8) | 0xff;
                    break;

                case 4:
                    bpc = 4;
                    break;

                case 8:
                    bpc = 8;
                    break;

                default:
                    return false;
        }

        const unsigned int single_max = (1 << bpc) - 1;
        result->r = ((n >> 3 * bpc) & single_max) / (double)single_max;
        result->g = ((n >> 2 * bpc) & single_max) / (double)single_max;
        result->b = ((n >> 1 * bpc) & single_max) / (double)single_max;
        result->a = ((n >> 0 * bpc) & single_max) / (double)single_max;
        return true;
    }

    log_debug("Invalid color '%s'", value);
    return false;
}

static bool config_read_gradient(const char *value, gradient_t *result)
{
    size_t count = 0;
    for (size_t i = 0; value[i] != '\0'; ++i)
        count += value[i] == ',';

    color_t *colors = calloc(count + 1, sizeof(color_t));
    size_t n = 0;

    char *state, *copy = strcopy(value);
    for (char *string = copy; ; string = NULL) {
        char *token = strtok_r(string, ",", &state);

        if (token == NULL)
            break;

        while (isspace(*token)) token++;
        char *end = token + strlen(token);
        while (isspace(*end)) end--;
        *end = '\0';

        if (!config_read_color(token, &colors[n++])) {
            free(copy);
            free(colors);
            return false;
        }
    }

    free(copy);
    result->colors = colors;
    result->length = n;

    if (n == 0) {
        free(colors);
        log_debug("Expected at least one color");
        return false;
    }

    if (n == 1) {
        result->pattern = cairo_pattern_create_rgba(colors->r, colors->g, colors->b, colors->a);
        return true;
    }

    result->pattern = cairo_pattern_create_linear(0, 0, 1, 0);
    for (size_t i = 0; i < n; i++) {
        double offset = i * 1.0 / (n - 1);
        cairo_pattern_add_color_stop_rgba(result->pattern, offset,
                colors[i].r, colors[i].g, colors[i].b, colors[i].a);
    }

    return true;
}

static bool config_read_enum(const char *value, config_enum_t *data, int *result)
{
    for (size_t i = 0; data[i].label != NULL; i++) {
        if (!strcmp(value, data[i].label)) {
            *result = data[i].value;
            return true;
        }
    }

    log_debug("Invalid enum value '%s'", value);
    return false;
}

// TODO: More robust parsing
static bool config_read_time(const char *value, struct timespec *result)
{
    unsigned int ms;
    if (config_read_uint(value, &ms)) {
        result->tv_sec = ms / 1000;
        result->tv_nsec = (ms % 1000) * 1000000;
        return true;
    }

    log_debug("Invalid time '%s'", value);
    return false;
}

// TODO: Handle quotation marks
static bool config_read_list(const char *value, char ***result)
{
    size_t count = 0;
    for (size_t i = 0; value[i] != '\0'; ++i)
        count += value[i] == ',';

    char **list = calloc(count + 2, sizeof(char *));
    size_t n = 0;

    char *state, *copy = strcopy(value);
    for (char *string = copy; ; string = NULL) {
        char *token = strtok_r(string, ",", &state);

        if (token == NULL)
            break;

        while (isspace(*token)) token++;
        char *end = token + strlen(token);
        while (isspace(*end)) end--;
        *end = '\0';

        if (!config_read_string(token, &list[n++])) {
            free(copy);
            free(list);
            return false;
        }
    }

    free(copy);
    list[n] = NULL;
    *result = list;
    return true;
}

static config_status_t config_read_entry(const config_entry_t *entries, void *result, const char **type,
                                         const char *section, const char *key, const char *value)
{
    static const char *types[] = {
        "string",
        "integer",
        "unsigned integer",
        "double float",
        "boolean",
        "color",
        "gradient",
        "enum",
        "time",
        "list",
    };

    for (size_t i = 0; entries[i].key != NULL; i++) {
        if (!strcmp(key, entries[i].key)) {
            if (type != NULL)
                *type = types[entries[i].type];

            result += entries[i].offset;
            bool nullable = type == CONFIG_STRING;
            if ((value == NULL || *value == '\0') && !nullable)
                return CONFIG_INVALID;

            switch (entries[i].type) {
                case CONFIG_STRING:
                    // NOTE: The previous string is freed by config_read_string
                    if (config_read_string(value, (char **)result)) {
                        log_debug("Set '%s.%s' to '%s'", section, key, *(char **)result);
                        return CONFIG_SUCCESS;
                    }
                    break;

                case CONFIG_INT:
                    if (config_read_int(value, (int *)result)) {
                        log_debug("Set '%s.%s' to '%d'", section, key, *(int *)result);
                        return CONFIG_SUCCESS;
                    }
                    break;

                case CONFIG_UINT:
                    if (config_read_uint(value, (unsigned int *)result)) {
                        log_debug("Set '%s.%s' to '%u'", section, key, *(unsigned int *)result);
                        return CONFIG_SUCCESS;
                    }
                    break;

                case CONFIG_DOUBLE:
                    if (config_read_double(value, (double *)result)) {
                        log_debug("Set '%s.%s' to '%lf'", section, key, *(double *)result);
                        return CONFIG_SUCCESS;
                    }
                    break;

                case CONFIG_BOOL:
                    if (config_read_bool(value, (bool *)result)) {
                        log_debug("Set '%s.%s' to '%s'", section, key, *(bool *)result ? "true" : "false");
                        return CONFIG_SUCCESS;
                    }
                    break;

                case CONFIG_COLOR:
                    if (config_read_color(value, (color_t *)result)) {
                        char *color = color_to_string((color_t *)result);
                        log_debug("Set '%s.%s' to '%s'", section, key, color);
                        free(color);
                        return CONFIG_SUCCESS;
                    }
                    break;

                case CONFIG_GRADIENT:
                    if (config_read_gradient(value, (gradient_t *)result)) {
                        char *gradient = gradient_to_string((gradient_t *)result);
                        log_debug("Set '%s.%s' to '%s'", section, key, gradient);
                        free(gradient);
                        return CONFIG_SUCCESS;
                    }
                    break;

                case CONFIG_ENUM:
                    if (config_read_enum(value, (config_enum_t *)entries[i].data, (int *)result)) {
                        log_debug("Set '%s.%s' to '%d'", section, key, *(int *)result);
                        return CONFIG_SUCCESS;
                    }
                    break;

                case CONFIG_TIME:
                    if (config_read_time(value, (struct timespec *)result)) {
                        log_debug("Set '%s.%s' to '%s'", section, key, value);
                        return CONFIG_SUCCESS;
                    }
                    break;

                case CONFIG_LIST:
                    if (config_read_list(value, (char ***)result)) {
                        log_debug("Set '%s.%s' to '%s'", section, key, value);
                        return CONFIG_SUCCESS;
                    }
                    break;

                default:
                    unreachable();
            }

            return CONFIG_INVALID;
        }
    }

    return CONFIG_UNKNOWN;
}

static config_status_t config_read_block(const block_scheme_t *scheme, block_t *block, const char **type,
                                         const char *section, const char *key, const char *value)
{
    config_status_t status = config_read_entry(block_entries, block, type, section, key, value);
    if (status != CONFIG_UNKNOWN) return status;

    status = config_read_entry(block->type == BLOCK_GROUP ? block_group_entries : block_text_entries,
                               block, type, section, key, value);

    return status != CONFIG_UNKNOWN || scheme == NULL || scheme->entries == NULL
        ? status
        : config_read_entry(scheme->entries, block, type, section, key, value);
}

static block_t *config_alloc_block(config_t *config, const block_scheme_t *scheme, char *label)
{
    config->blocks = realloc(config->blocks, ++config->n_blocks * sizeof(block_t *));
    assert(config->blocks != NULL);

    block_t *block = config->blocks[config->n_blocks - 1] = calloc(1, scheme->size);
    assert(block != NULL);

    block->label = label;
    block->scheme = scheme;
    scheme->init_fn(block);

    return block;
}

static config_status_t config_read_action(action_t *action, const char **type,
                                          const char *section, const char *key, const char *value)
{
    action->parts = realloc(action->parts, ++action->length * sizeof(action_part_t));
    assert(action->parts != NULL);

    action->parts[action->length - 1].key = strcopy(key);
    action->parts[action->length - 1].value = strcopy(key);

    return CONFIG_SUCCESS;
}

// TODO: More robust way to define defaults
void config_init(config_t *config)
{
    const config_t config_default = {
        .font = "monospace 10",
        .monitor = NULL,
        .width = 100,
        .height = 50,
        .override_redirect = false,
    };

    memcpy(config, &config_default, sizeof(config_t));
    config->font = strcopy(config_default.font);

    extern const block_scheme_t block_group_scheme;
    block_group_t *bar = (block_group_t *)config_alloc_block(config, &block_group_scheme, strcopy("bar"));
    bar->spacing = 10;
}

int config_read(config_t *config, FILE *file)
{
    any_ini_stream_t ini;
    any_ini_file_init(&ini, file);

    int n_errors = 0;
    char *section = NULL;

    do {
        char *key = NULL, *value = NULL;
        int errors = 0;

        bool bar_section = false;
        action_t *action = NULL;

        const block_scheme_t *scheme = NULL;
        block_t *block = NULL;

        if (section != NULL) {
            if (!strncmp(section, "block.", 6)) {
                char *label = strcopy(section + 6);
                if (label == NULL || *label == '\0' || !strcmp(label, "bar")) {
                    ++errors;
                    log_value_error("Block section must have a valid label",
                                    "s:section", section,
                                    "i:line", ini.line);
                } else {
                    for (size_t i = 0; i < config->n_blocks; i++) {
                        if (!strcmp(label, config->blocks[i]->label)) {
                            ++errors;
                            log_value_error("Block section must have a unique label",
                                            "s:section", section,
                                            "i:line", ini.line);
                        }
                    }
                }

                if ((key = any_ini_stream_next_key(&ini)) == NULL || strcmp(key, "type")) {
                    ++errors;
                    log_value_error("Block section must start with a 'type' pair",
                                    "s:section", section,
                                    "s:wrong_key", key,
                                    "i:line", ini.line);
                    goto skip_pair;
                }

                value = any_ini_stream_next_value(&ini);
                if (value == NULL) {
                    ++errors;
                    log_value_error("Block type must be non-empty",
                                    "s:section", section,
                                    "i:line", ini.line);
                    goto skip_pair;
                }

                for (size_t i = 0; block_schemes[i] != NULL; i++) {
                    if (strcmp(block_schemes[i]->name, value))
                        continue;

                    scheme = block_schemes[i];
                    block = config_alloc_block(config, scheme, label);
                    goto skip_pair;
                }

                ++errors;
                log_value_error("Block type not supported",
                                "s:section", section,
                                "s:type", value,
                                "i:line", ini.line);

                goto skip_pair;
            } else if (!strncmp(section, "action.", 7)) {
                char *label = strcopy(section + 7);

                if (label == NULL || *label == '\0') {
                    ++errors;
                    log_value_error("Action section must have a valid label",
                                    "s:section", section,
                                    "i:line", ini.line);
                } else {
                    for (size_t i = 0; i < config->n_actions; i++) {
                        if (!strcmp(label, config->actions[i].label)) {
                            ++errors;
                            log_value_error("Action section must have a unique label",
                                            "s:section", section,
                                            "i:line", ini.line);
                        }
                    }
                }

                config->actions = realloc(config->actions, ++config->n_actions * sizeof(action_t));
                assert(config->actions != NULL);

                action = &config->actions[config->n_actions - 1];
                memset(action, 0, sizeof(action_t));
                action->label = label;

            } else if (!strcmp(section, "bar")) {
                bar_section = true;
            } else
                log_warn("Unknown section '%s'", section);
        }

        while ((key = any_ini_stream_next_key(&ini)) != NULL) {
            value = any_ini_stream_next_value(&ini);

            log_value_trace("Reading entry",
                            "s:section", section,
                            "s:key", key,
                            "s:value", value,
                            "i:line", ini.line);

            if (!bar_section && block == NULL)
                 goto skip_pair;

            const char *type;
            config_status_t status;

            if (bar_section) {
                status = config_read_entry(bar_entries, config, &type, section, key, value);

                // Try the block entries
                if (status == CONFIG_UNKNOWN)
                    block = config->blocks[0];
            }

            if (block != NULL) {
                status = config_read_block(scheme, block, &type, section, key, value);
            }

            if (action != NULL) {
                status = config_read_action(action, &type, section, key, value);
            }

            switch (status) {
                case CONFIG_SUCCESS:
                    break;

                case CONFIG_INVALID:
                    errors++;
                    log_value_error("Invalid entry",
                                    "s:section", section,
                                    "s:key", key,
                                    "s:value", value,
                                    "s:type", type,
                                    "i:line", ini.line);
                    break;

                case CONFIG_UNKNOWN:
                    log_value_warn("Unknown entry",
                                   "s:section", section,
                                   "s:key", key,
                                   "s:value", value,
                                   "i:line", ini.line);
                    break;

                default:
                    unreachable();
            }

skip_pair:
            free(key);
            free(value);
        }

        free(section);
        n_errors += errors;
    } while ((section = any_ini_stream_next_section(&ini)) != NULL);

    return n_errors;
}

int config_validate(config_t *config)
{
    int errors = 0;

    // Validate the config itself
    if (config->scale < 1 && config->scale != 0) {
        log_error("Bar '%s' should be at least 1", "scale");
        errors++;
    }

    // Validate blocks
    for (size_t i = 0; i < config->n_blocks; i++) {
        block_t *block = config->blocks[i];
        const block_scheme_t *scheme = block->scheme;

        if (scheme->validate_fn == NULL) continue;
        log_debug("Validating 'block.%s'", block->label);

        int tmp = scheme->validate_fn(block);
        errors += tmp;
        block->validated = tmp == 0;
    }

    // Validate actions
    // NOTE: Maybe move this after the config is resolved?
    //
    for (size_t i = 0; i < config->n_actions; i++) {
        action_t *action = &config->actions[i];
        log_debug("Validating 'action.%s'", action->label);
        errors += action_validate(action, config);
    }

    return errors;
}

bool config_resolve_children(config_t *config, block_t *block)
{
    block->resolved = true;

    if (block->type != BLOCK_GROUP)
        return true;

    assert(block->type == BLOCK_GROUP);
    block_group_t *group = (block_group_t *)block;

    char **children = (char **)group->children;
    group->children = NULL;
    group->n_children = 0;

    if (children == NULL)
        return true;

    while (children[group->n_children] != NULL)
        group->n_children++;

    group->children = malloc(group->n_children * sizeof(block_t *));

    for (size_t i = 0; i < group->n_children; i++) {
        for (size_t j = 0; j < config->n_blocks; j++) {
            if (config->blocks[j] == block)
                continue;

            if (!strcmp(children[i], config->blocks[j]->label)) {
                if (config->blocks[j]->resolved) {
                    log_error("Block '%s' can only be referenced by one block", config->blocks[j]->label);
                    goto error;
                }

                log_debug("Block '%s' is parent of '%s'", block->label, config->blocks[j]->label);
                group->children[i] = config->blocks[j];

                if (!config_resolve_children(config, config->blocks[j]))
                    goto error;
                goto next;
            }
        }

        log_error("Block '%s' not found", children[i]);
        goto error;
next:
    }

    strfree(children);
    return true;

error:
    strfree(children);
    return false;
}

int config_resolve(config_t *config, block_t **block)
{
    int errors = 0;
    block_group_t *bar = (block_group_t *)config->blocks[0];

    if (bar->children == NULL) {
        errors++;
        log_error("Section '%s' requires at least one child", "bar");
    } else {
        // NOTE: The first item is the main block
        bar->block.min_width = bar->block.max_width = config->width;
        errors += !config_resolve_children(config, config->blocks[0]);
    }

    *block = config->blocks[0];
    return errors;
}

void config_free(config_t *config)
{
    for (size_t i = 0; i < config->n_blocks; i++)
        block_free(config->blocks[i]);

    for (size_t i = 0; i < config->n_actions; i++)
        action_free(&config->actions[i]);

    gradient_free(&config->background);

    free(config->blocks);
    free(config->font);
    free(config->monitor);
}