package sse

import (
	"bytes"
	"encoding/json"
	"strings"

	"ds2api/internal/deepseek"
)

type ContentPart struct {
	Text string
	Type string
}

func ParseDeepSeekSSELine(raw []byte) (map[string]any, bool, bool) {
	line := strings.TrimSpace(string(raw))
	if line == "" || !strings.HasPrefix(line, "data:") {
		return nil, false, false
	}
	dataStr := strings.TrimSpace(strings.TrimPrefix(line, "data:"))
	if dataStr == "[DONE]" {
		return nil, true, true
	}
	chunk := map[string]any{}
	if err := json.Unmarshal([]byte(dataStr), &chunk); err != nil {
		return nil, false, false
	}
	return chunk, false, true
}

func shouldSkipPath(path string) bool {
	if _, ok := deepseek.SkipExactPathSet[path]; ok {
		return true
	}
	for _, p := range deepseek.SkipContainsPatterns {
		if strings.Contains(path, p) {
			return true
		}
	}
	return false
}

func ParseSSEChunkForContent(chunk map[string]any, thinkingEnabled bool, currentFragmentType string) ([]ContentPart, bool, string) {
	v, ok := chunk["v"]
	if !ok {
		return nil, false, currentFragmentType
	}
	path, _ := chunk["p"].(string)
	if shouldSkipPath(path) {
		return nil, false, currentFragmentType
	}
	if path == "response/status" {
		if s, ok := v.(string); ok && s == "FINISHED" {
			return nil, true, currentFragmentType
		}
	}
	newType := currentFragmentType
	parts := make([]ContentPart, 0, 8)
	collectDirectFragments(path, chunk, v, &newType, &parts)
	updateTypeFromNestedResponse(path, v, &newType)
	partType := resolvePartType(path, thinkingEnabled, newType)
	finished := appendChunkValueContent(v, partType, &newType, &parts, path)
	if finished {
		return nil, true, newType
	}
	return parts, false, newType
}

func collectDirectFragments(path string, chunk map[string]any, v any, newType *string, parts *[]ContentPart) {
	if path != "response/fragments" {
		return
	}
	op, _ := chunk["o"].(string)
	if !strings.EqualFold(op, "APPEND") {
		return
	}
	frags, ok := v.([]any)
	if !ok {
		return
	}
	for _, frag := range frags {
		m, ok := frag.(map[string]any)
		if !ok {
			continue
		}
		typeName, content, fragType := parseFragmentTypeContent(m)
		if typeName == "" {
			typeName = fragType
		}
		switch typeName {
		case "THINK", "THINKING":
			*newType = "thinking"
			appendContentPart(parts, content, "thinking")
		case "RESPONSE":
			*newType = "text"
			appendContentPart(parts, content, "text")
		default:
			appendContentPart(parts, content, "text")
		}
	}
}

func updateTypeFromNestedResponse(path string, v any, newType *string) {
	if path != "response" {
		return
	}
	arr, ok := v.([]any)
	if !ok {
		return
	}
	for _, it := range arr {
		m, ok := it.(map[string]any)
		if !ok || m["p"] != "fragments" || m["o"] != "APPEND" {
			continue
		}
		frags, ok := m["v"].([]any)
		if !ok {
			continue
		}
		for _, frag := range frags {
			fm, ok := frag.(map[string]any)
			if !ok {
				continue
			}
			typeName, _, _ := parseFragmentTypeContent(fm)
			switch typeName {
			case "THINK", "THINKING":
				*newType = "thinking"
			case "RESPONSE":
				*newType = "text"
			}
		}
	}
}

func resolvePartType(path string, thinkingEnabled bool, newType string) string {
	switch {
	case path == "response/thinking_content":
		return "thinking"
	case path == "response/content":
		return "text"
	case strings.Contains(path, "response/fragments") && strings.Contains(path, "/content"):
		return newType
	case path == "" && thinkingEnabled:
		return newType
	default:
		return "text"
	}
}

func appendChunkValueContent(v any, partType string, newType *string, parts *[]ContentPart, path string) bool {
	switch val := v.(type) {
	case string:
		if val == "FINISHED" && (path == "" || path == "status") {
			return true
		}
		appendContentPart(parts, val, partType)
	case []any:
		pp, finished := extractContentRecursive(val, partType)
		if finished {
			return true
		}
		*parts = append(*parts, pp...)
	case map[string]any:
		appendWrappedFragments(val, partType, newType, parts)
	}
	return false
}

func appendWrappedFragments(val map[string]any, partType string, newType *string, parts *[]ContentPart) {
	resp := val
	if wrapped, ok := val["response"].(map[string]any); ok {
		resp = wrapped
	}
	frags, ok := resp["fragments"].([]any)
	if !ok {
		return
	}
	for _, item := range frags {
		m, ok := item.(map[string]any)
		if !ok {
			continue
		}
		typeName, content, fragType := parseFragmentTypeContent(m)
		if typeName == "" {
			typeName = fragType
		}
		switch typeName {
		case "THINK", "THINKING":
			*newType = "thinking"
			appendContentPart(parts, content, "thinking")
		case "RESPONSE":
			*newType = "text"
			appendContentPart(parts, content, "text")
		default:
			appendContentPart(parts, content, partType)
		}
	}
}

func parseFragmentTypeContent(m map[string]any) (string, string, string) {
	typeName, _ := m["type"].(string)
	content, _ := m["content"].(string)
	return strings.ToUpper(typeName), content, strings.ToUpper(typeName)
}

func appendContentPart(parts *[]ContentPart, content, kind string) {
	if content == "" {
		return
	}
	*parts = append(*parts, ContentPart{Text: content, Type: kind})
}

func extractContentRecursive(items []any, defaultType string) ([]ContentPart, bool) {
	parts := make([]ContentPart, 0, len(items))
	for _, it := range items {
		m, ok := it.(map[string]any)
		if !ok {
			continue
		}
		itemPath, _ := m["p"].(string)
		itemV, hasV := m["v"]
		if !hasV {
			continue
		}
		if itemPath == "status" {
			if s, ok := itemV.(string); ok && s == "FINISHED" {
				return nil, true
			}
		}
		if shouldSkipPath(itemPath) {
			continue
		}
		if content, ok := m["content"].(string); ok && content != "" {
			typeName, _ := m["type"].(string)
			typeName = strings.ToUpper(typeName)
			switch typeName {
			case "THINK", "THINKING":
				parts = append(parts, ContentPart{Text: content, Type: "thinking"})
			case "RESPONSE":
				parts = append(parts, ContentPart{Text: content, Type: "text"})
			default:
				parts = append(parts, ContentPart{Text: content, Type: defaultType})
			}
			continue
		}
		partType := defaultType
		if strings.Contains(itemPath, "thinking") {
			partType = "thinking"
		} else if strings.Contains(itemPath, "content") || itemPath == "response" || itemPath == "fragments" {
			partType = "text"
		}
		switch v := itemV.(type) {
		case string:
			if v != "" && v != "FINISHED" {
				parts = append(parts, ContentPart{Text: v, Type: partType})
			}
		case []any:
			for _, inner := range v {
				switch x := inner.(type) {
				case map[string]any:
					ct, _ := x["content"].(string)
					if ct == "" {
						continue
					}
					typeName, _ := x["type"].(string)
					typeName = strings.ToUpper(typeName)
					if typeName == "THINK" || typeName == "THINKING" {
						parts = append(parts, ContentPart{Text: ct, Type: "thinking"})
					} else if typeName == "RESPONSE" {
						parts = append(parts, ContentPart{Text: ct, Type: "text"})
					} else {
						parts = append(parts, ContentPart{Text: ct, Type: partType})
					}
				case string:
					if x != "" {
						parts = append(parts, ContentPart{Text: x, Type: partType})
					}
				}
			}
		}
	}
	return parts, false
}

func IsCitation(text string) bool {
	return bytes.HasPrefix([]byte(strings.TrimSpace(text)), []byte("[citation:"))
}