package admin

import (
	"encoding/json"
	"fmt"
	"net/http"
	"strconv"

	"github.com/gin-gonic/gin"
	"go.uber.org/zap"
	"gorm.io/gorm"

	"openteam/server/internal/channel"
	"openteam/server/internal/pkg/httpx"
	"openteam/server/internal/store"
)

type channelHandler struct {
	db  *gorm.DB
	ch  *channel.Service
	log *zap.Logger
}

type channelInput struct {
	Name           string   `json:"name" binding:"required"`
	Provider       string   `json:"provider" binding:"omitempty,oneof=openai anthropic compatible"`
	BaseURL        string   `json:"baseUrl" binding:"required"`
	APIKey         string   `json:"apiKey"`
	Weight         int      `json:"weight"`
	Priority       int      `json:"priority"`
	TimeoutMs      int      `json:"timeoutMs"`
	MaxConcurrency int      `json:"maxConcurrency"`
	Enabled        *bool    `json:"enabled"`
	Formats        []string `json:"formats"`
}

// ListChannels handles GET /api/v1/admin/channels.
func (h *channelHandler) List(c *gin.Context) {
	var channels []store.Channel
	if err := h.db.Order("id ASC").Find(&channels).Error; err != nil {
		h.log.Warn("list channels failed", zap.Error(err))
		httpx.Fail(c, http.StatusInternalServerError, "list channels failed")
		return
	}
	out := make([]gin.H, 0, len(channels))
	for i := range channels {
		out = append(out, channelDTO(&channels[i]))
	}
	httpx.OK(c, out)
}

// Create handles POST /api/v1/admin/channels.
func (h *channelHandler) Create(c *gin.Context) {
	var in channelInput
	if !httpx.Bind(c, &in) {
		return
	}
	provider := in.Provider
	if len(in.Formats) > 0 {
		if err := validateFormats(in.Formats); err != nil {
			httpx.Fail(c, http.StatusBadRequest, err.Error())
			return
		}
		provider = deriveProvider(in.Formats)
	}
	if provider == "" {
		provider = "openai"
	}
	enc, err := h.ch.EncryptKey(in.APIKey)
	if err != nil {
		httpx.Fail(c, http.StatusInternalServerError, "encrypt key failed")
		return
	}
	ch := &store.Channel{
		Name: in.Name, Provider: provider, BaseURL: in.BaseURL, Formats: in.Formats,
		APIKeyEnc: enc, Weight: defaultIf(in.Weight, 1), Priority: in.Priority,
		TimeoutMs: defaultIf(in.TimeoutMs, 300000), MaxConcurrency: defaultIf(in.MaxConcurrency, 100),
		Enabled: true,
	}
	if in.Enabled != nil {
		ch.Enabled = *in.Enabled
	}
	if err := h.db.Create(ch).Error; err != nil {
		h.log.Warn("create channel failed", zap.Error(err))
		httpx.Fail(c, http.StatusInternalServerError, "create channel failed")
		return
	}
	httpx.Created(c, channelDTO(ch))
}

// Update handles PUT /api/v1/admin/channels/:id.
func (h *channelHandler) Update(c *gin.Context) {
	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
	if err != nil {
		httpx.Fail(c, http.StatusBadRequest, "invalid channel id")
		return
	}
	var ch store.Channel
	if err := h.db.First(&ch, id).Error; err != nil {
		httpx.Fail(c, http.StatusNotFound, "channel not found")
		return
	}
	var in channelInput
	if !httpx.Bind(c, &in) {
		return
	}
	updates := map[string]any{
		"name": in.Name, "base_url": in.BaseURL,
		"weight": defaultIf(in.Weight, ch.Weight), "priority": in.Priority,
		"timeout_ms": defaultIf(in.TimeoutMs, ch.TimeoutMs),
		"max_concurrency": defaultIf(in.MaxConcurrency, ch.MaxConcurrency),
	}
	if len(in.Formats) > 0 {
		if err := validateFormats(in.Formats); err != nil {
			httpx.Fail(c, http.StatusBadRequest, err.Error())
			return
		}
		updates["provider"] = deriveProvider(in.Formats)
		// GORM map updates skip the json serializer, so encode explicitly;
		// a raw []string would be emitted as a SQL row-value list.
		formatsJSON, err := json.Marshal(in.Formats)
		if err != nil {
			httpx.Fail(c, http.StatusInternalServerError, "serialize formats failed")
			return
		}
		updates["formats"] = string(formatsJSON)
	} else if in.Provider != "" {
		updates["provider"] = in.Provider
	}
	if in.Enabled != nil {
		updates["enabled"] = *in.Enabled
	}
	if in.APIKey != "" {
		enc, err := h.ch.EncryptKey(in.APIKey)
		if err != nil {
			httpx.Fail(c, http.StatusInternalServerError, "encrypt key failed")
			return
		}
		updates["api_key_enc"] = enc
	}
	if err := h.db.Model(&ch).Updates(updates).Error; err != nil {
		h.log.Warn("update channel failed", zap.Error(err))
		httpx.Fail(c, http.StatusInternalServerError, "update channel failed")
		return
	}
	h.db.First(&ch, id)
	httpx.OK(c, channelDTO(&ch))
}

// Delete handles DELETE /api/v1/admin/channels/:id.
func (h *channelHandler) Delete(c *gin.Context) {
	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
	if err != nil {
		httpx.Fail(c, http.StatusBadRequest, "invalid channel id")
		return
	}
	if err := h.db.Transaction(func(tx *gorm.DB) error {
		if err := tx.Where("channel_id = ?", id).Delete(&store.ChannelModelBinding{}).Error; err != nil {
			return err
		}
		return tx.Delete(&store.Channel{}, id).Error
	}); err != nil {
		h.log.Warn("delete channel failed", zap.Error(err))
		httpx.Fail(c, http.StatusInternalServerError, "delete channel failed")
		return
	}
	httpx.OK(c, gin.H{"ok": true})
}

// Test handles POST /api/v1/admin/channels/:id/test.
func (h *channelHandler) Test(c *gin.Context) {
	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
	if err != nil {
		httpx.Fail(c, http.StatusBadRequest, "invalid channel id")
		return
	}
	var ch store.Channel
	if err := h.db.First(&ch, id).Error; err != nil {
		httpx.Fail(c, http.StatusNotFound, "channel not found")
		return
	}
	ok, latency, model, err := h.ch.Test(&ch)
	if err != nil || !ok {
		msg := "test failed"
		if err != nil {
			msg = err.Error()
		}
		httpx.Fail(c, http.StatusBadGateway, msg)
		return
	}
	httpx.OK(c, gin.H{"ok": true, "latencyMs": latency, "model": model})
}

// ImportModels handles POST /api/v1/admin/channels/:id/import-models.
func (h *channelHandler) ImportModels(c *gin.Context) {
	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
	if err != nil {
		httpx.Fail(c, http.StatusBadRequest, "invalid channel id")
		return
	}
	var ch store.Channel
	if err := h.db.First(&ch, id).Error; err != nil {
		httpx.Fail(c, http.StatusNotFound, "channel not found")
		return
	}
	names, err := h.ch.ImportModels(&ch)
	if err != nil {
		httpx.Fail(c, http.StatusBadGateway, "import failed: "+err.Error())
		return
	}
	httpx.OK(c, gin.H{"imported": names, "count": len(names)})
}

// ListBindings handles GET /api/v1/admin/channels/:id/bindings.
func (h *channelHandler) ListBindings(c *gin.Context) {
	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
	if err != nil {
		httpx.Fail(c, http.StatusBadRequest, "invalid channel id")
		return
	}
	var bindings []store.ChannelModelBinding
	if err := h.db.Preload("Model").Where("channel_id = ?", id).Find(&bindings).Error; err != nil {
		h.log.Warn("list bindings failed", zap.Error(err))
		httpx.Fail(c, http.StatusInternalServerError, "list bindings failed")
		return
	}
	out := make([]gin.H, 0, len(bindings))
	for _, b := range bindings {
		out = append(out, gin.H{
			"id": b.ID, "modelId": b.ModelID, "modelName": b.Model.Name,
			"upstreamModel": b.UpstreamModel, "weight": b.Weight,
		})
	}
	httpx.OK(c, out)
}

// SaveBindings handles PUT /api/v1/admin/channels/:id/bindings.
func (h *channelHandler) SaveBindings(c *gin.Context) {
	id, err := strconv.ParseInt(c.Param("id"), 10, 64)
	if err != nil {
		httpx.Fail(c, http.StatusBadRequest, "invalid channel id")
		return
	}
	var in struct {
		Items []struct {
			ModelID       int64  `json:"modelId"`
			UpstreamModel string `json:"upstreamModel"`
			Weight        int    `json:"weight"`
		} `json:"items"`
	}
	if !httpx.Bind(c, &in) {
		return
	}
	if err := h.db.Transaction(func(tx *gorm.DB) error {
		if err := tx.Where("channel_id = ?", id).Delete(&store.ChannelModelBinding{}).Error; err != nil {
			return err
		}
		for _, item := range in.Items {
			if item.ModelID == 0 {
				continue
			}
			b := store.ChannelModelBinding{
				ChannelID: id, ModelID: item.ModelID,
				UpstreamModel: item.UpstreamModel, Weight: defaultIf(item.Weight, 1),
			}
			if err := tx.Create(&b).Error; err != nil {
				return err
			}
		}
		return nil
	}); err != nil {
		h.log.Warn("save bindings failed", zap.Error(err))
		httpx.Fail(c, http.StatusInternalServerError, "save bindings failed")
		return
	}
	httpx.OK(c, gin.H{"ok": true})
}

func channelDTO(ch *store.Channel) gin.H {
	return gin.H{
		"id": ch.ID, "name": ch.Name, "provider": ch.Provider, "baseUrl": ch.BaseURL,
		"formats": ch.FormatsResolved(),
		"weight": ch.Weight, "priority": ch.Priority, "timeoutMs": ch.TimeoutMs,
		"maxConcurrency": ch.MaxConcurrency, "healthStatus": ch.HealthStatus,
		"healthFailures": ch.HealthFailures, "enabled": ch.Enabled,
		"createdAt": ch.CreatedAt, "updatedAt": ch.UpdatedAt,
	}
}

var validFormats = map[string]bool{
	store.FormatOpenAIChat:      true,
	store.FormatOpenAIResponses: true,
	store.FormatAnthropic:       true,
}

func validateFormats(fs []string) error {
	for _, f := range fs {
		if !validFormats[f] {
			return fmt.Errorf("invalid api format: %s", f)
		}
	}
	return nil
}

// deriveProvider computes the conversion-target provider from the declared
// formats. Anthropic-only channels convert to Claude; anything else targets the
// OpenAI chat-completions family.
func deriveProvider(formats []string) string {
	hasAnthropic, hasOpenAI := false, false
	for _, f := range formats {
		switch f {
		case store.FormatAnthropic:
			hasAnthropic = true
		case store.FormatOpenAIChat, store.FormatOpenAIResponses:
			hasOpenAI = true
		}
	}
	if hasAnthropic && !hasOpenAI {
		return "anthropic"
	}
	return "openai"
}

func defaultIf(v, def int) int {
	if v == 0 {
		return def
	}
	return v
}