package topdata

import (
	"fmt"
	"os"
	"strings"

	"gopkg.in/yaml.v3"
)

type wikiDataProvidersDocument struct {
	Providers map[string]wikiDataProviderDefinition `json:"providers" yaml:"providers"`
}

type wikiDataProviderDefinition struct {
	Source string `json:"source" yaml:"source"`
	Levels string `json:"levels" yaml:"levels"`
}

func loadWikiDataProviders(path string) (map[string]wikiDataProviderDefinition, error) {
	raw, err := os.ReadFile(path)
	if err != nil {
		if os.IsNotExist(err) {
			return map[string]wikiDataProviderDefinition{}, nil
		}
		return nil, fmt.Errorf("read wiki data providers %s: %w", path, err)
	}
	var doc wikiDataProvidersDocument
	if err := yaml.Unmarshal(raw, &doc); err != nil {
		return nil, fmt.Errorf("parse wiki data providers %s: %w", path, err)
	}
	for name, def := range doc.Providers {
		if strings.TrimSpace(name) == "" {
			return nil, fmt.Errorf("wiki data providers %s: provider name must not be empty", path)
		}
		if strings.TrimSpace(def.Source) == "" {
			return nil, fmt.Errorf("wiki data providers %s: provider %s missing source", path, name)
		}
		switch strings.TrimSpace(def.Source) {
		case "class_progression", "class_feats", "class_summary", "race_feats", "race_name_forms":
		default:
			return nil, fmt.Errorf("wiki data providers %s: provider %s has unknown source %q", path, name, def.Source)
		}
	}
	if doc.Providers == nil {
		return map[string]wikiDataProviderDefinition{}, nil
	}
	return doc.Providers, nil
}

func (ctx *wikiContext) wikiDataProviderRows(name string, page wikiTemplatePage) ([]map[string]any, error) {
	def, ok := ctx.wikiDataProviders[name]
	if !ok {
		return nil, fmt.Errorf("missing wiki data provider %q in %s", name, ctx.wikiDataPath)
	}
	switch strings.TrimSpace(def.Source) {
	case "class_progression":
		if page.Category != "classes" {
			return nil, nil
		}
		return ctx.classProgressionRows(wikiTableDefinition{Rows: wikiTableRowsConfig{Levels: def.Levels}}, page.Row)
	case "class_feats":
		if page.Category != "classes" {
			return nil, nil
		}
		return ctx.classFeatRows(page.Row), nil
	case "class_summary":
		if page.Category != "classes" {
			return nil, nil
		}
		return ctx.classSummaryRows(page.Row), nil
	case "race_feats":
		if page.Category != "racialtypes" {
			return nil, nil
		}
		return ctx.raceFeatRows(page.Row), nil
	case "race_name_forms":
		if page.Category != "racialtypes" {
			return nil, nil
		}
		return ctx.raceNameFormRows(page.Row), nil
	default:
		return nil, fmt.Errorf("unknown wiki data provider source %q", def.Source)
	}
}

func (ctx *wikiContext) raceFeatRows(raceRow map[string]any) []map[string]any {
	values := []any{}
	switch typed := fieldValue(raceRow, "FeatsTable").(type) {
	case []any:
		values = append(values, typed...)
	case []string:
		for _, value := range typed {
			values = append(values, value)
		}
	default:
		if table := ctx.tableForValue(typed, ctx.raceFeatTables); table != nil {
			for _, row := range table.Rows {
				values = append(values, fieldValue(row, "FeatIndex"))
			}
		}
	}
	rows := []map[string]any{}
	for _, value := range values {
		key := resolveReferenceKey(value, ctx.featIDToKey)
		if key == "" {
			key = resolveReferenceKey(value, nil)
		}
		if key == "" || !ctx.canReferenceWikiKey(key) {
			continue
		}
		rows = append(rows, map[string]any{
			"FeatKey":  key,
			"FeatName": ctx.resolveFeatName(key),
		})
	}
	return rows
}

func (ctx *wikiContext) raceNameFormRows(raceRow map[string]any) []map[string]any {
	candidates := []struct {
		label string
		field string
	}{
		{"Plural", "NamePlural"},
		{"Converted Name", "ConverName"},
		{"Lower Name", "ConverNameLower"},
	}
	rows := []map[string]any{}
	for _, candidate := range candidates {
		if value := ctx.resolveTextValue(fieldValue(raceRow, candidate.field), nil); value != "" {
			rows = append(rows, map[string]any{"Label": candidate.label, "Value": value})
		}
	}
	return rows
}