package llmapi

import (
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"log/slog"
	"strings"
)

type RespParser interface {
	ParseBytes(body []byte) (map[string]any, error)
	MakePayload(prompt string) io.Reader
}

// DeepSeekParser: deepseek implementation of RespParser
type deepSeekParser struct {
	log *slog.Logger
}

func NewDeepSeekParser(log *slog.Logger) *deepSeekParser {
	return &deepSeekParser{log: log}
}

func (p *deepSeekParser) ParseBytes(body []byte) (map[string]any, error) {
	// parsing logic here
	dsResp := DSResp{}
	if err := json.Unmarshal(body, &dsResp); err != nil {
		p.log.Error("failed to unmarshall", "error", err)
		return nil, err
	}
	if len(dsResp.Choices) == 0 {
		p.log.Error("empty choices", "dsResp", dsResp)
		err := errors.New("empty choices in dsResp")
		return nil, err
	}
	text := dsResp.Choices[0].Text
	li := strings.Index(text, "{")
	ri := strings.LastIndex(text, "}")
	if li < 0 || ri < 1 {
		p.log.Error("not a json", "msg", text)
		err := fmt.Errorf("fn: ParseBytes, not a json; data: %s", text)
		return nil, err
	}
	sj := text[li : ri+1]
	respMap := make(map[string]any)
	if err := json.Unmarshal([]byte(sj), &respMap); err != nil {
		p.log.Error("failed to unmarshal response", "error", err, "string-json", sj)
		return nil, err
	}
	return respMap, nil
}

func (p *deepSeekParser) MakePayload(prompt string) io.Reader {
	return strings.NewReader(fmt.Sprintf(`{
	  "model": "deepseek-chat",
	  "prompt": "%s",
	  "echo": false,
	  "frequency_penalty": 0,
	  "logprobs": 0,
	  "max_tokens": 1024,
	  "presence_penalty": 0,
	  "stop": null,
	  "stream": false,
	  "stream_options": null,
	  "suffix": null,
	  "temperature": 1,
	  "top_p": 1
	}`, prompt))
}

// llama.cpp implementation of RespParser
type lcpRespParser struct {
	log *slog.Logger
}

func NewLCPRespParser(log *slog.Logger) *lcpRespParser {
	return &lcpRespParser{log: log}
}

func (p *lcpRespParser) ParseBytes(body []byte) (map[string]any, error) {
	// parsing logic here
	resp := LLMResp{}
	if err := json.Unmarshal(body, &resp); err != nil {
		p.log.Error("failed to unmarshal", "error", err)
		return nil, err
	}
	text := resp.Content
	li := strings.Index(text, "{")
	ri := strings.LastIndex(text, "}")
	if li < 0 || ri < 1 {
		p.log.Error("not a json", "msg", text)
		err := fmt.Errorf("fn: ParseBytes, not a json; data: %s", text)
		return nil, err
	}
	sj := text[li : ri+1]
	respMap := make(map[string]any)
	if err := json.Unmarshal([]byte(sj), &respMap); err != nil {
		p.log.Error("failed to unmarshal response", "error", err, "string-json", sj)
		return nil, err
	}
	return respMap, nil
}

func (p *lcpRespParser) MakePayload(prompt string) io.Reader {
	return strings.NewReader(fmt.Sprintf(`{
	  "model": "local-model",
	  "prompt": "%s",
	  "frequency_penalty": 0,
	  "max_tokens": 1024,
	  "stop": null,
	  "stream": false,
	  "temperature": 0.4,
	  "top_p": 1
	}`, prompt))
}

type openRouterParser struct {
	log        *slog.Logger
	modelIndex uint32
}

func NewOpenRouterParser(log *slog.Logger) *openRouterParser {
	return &openRouterParser{
		log:        log,
		modelIndex: 0,
	}
}

func (p *openRouterParser) ParseBytes(body []byte) (map[string]any, error) {
	// parsing logic here
	resp := OpenRouterResp{}
	if err := json.Unmarshal(body, &resp); err != nil {
		p.log.Error("failed to unmarshal", "error", err)
		return nil, err
	}
	if len(resp.Choices) == 0 {
		p.log.Error("empty choices", "resp", resp)
		err := errors.New("empty choices in resp")
		return nil, err
	}
	text := resp.Choices[0].Message.Content
	li := strings.Index(text, "{")
	ri := strings.LastIndex(text, "}")
	if li < 0 || ri < 1 {
		p.log.Error("not a json", "msg", text)
		err := fmt.Errorf("fn: ParseBytes, not a json; data: %s", text)
		return nil, err
	}
	sj := text[li : ri+1]
	respMap := make(map[string]any)
	if err := json.Unmarshal([]byte(sj), &respMap); err != nil {
		p.log.Error("failed to unmarshal response", "error", err, "string-json", sj)
		return nil, err
	}
	return respMap, nil
}

func (p *openRouterParser) MakePayload(prompt string) io.Reader {
	// Models to rotate through
	models := []string{
		"google/gemini-2.0-flash-exp:free",
		"deepseek/deepseek-chat-v3-0324:free",
		"mistralai/mistral-small-3.2-24b-instruct:free",
		"qwen/qwen3-14b:free",
		"deepseek/deepseek-r1:free",
		"google/gemma-3-27b-it:free",
		"meta-llama/llama-3.3-70b-instruct:free",
	}
	// Get next model index using atomic addition for thread safety
	p.modelIndex++
	model := models[int(p.modelIndex)%len(models)]
	strPayload := fmt.Sprintf(`{
	"model": "%s",
	"messages": [
		{
		"role": "user",
		"content": "%s"
		}
	]
	}`, model, prompt)
	p.log.Debug("made openrouter payload", "model", model, "payload", strPayload)
	return strings.NewReader(strPayload)
}