package config

import (
	"fmt"
	"strings"

	"gitea.maximumdirect.net/eric/notarius/internal/core/diagnostics"
	"gitea.maximumdirect.net/eric/notarius/internal/framework/pipeline"
)

const providerOpenAICompatible = "openai-compatible"

func (c Config) Validate() error {
	if err := validateLLMProfiles(c.LLMProfiles); err != nil {
		return err
	}
	if err := validateDiagnostics(c.Diagnostics); err != nil {
		return err
	}
	if c.Concurrency.TotalLLM <= 0 {
		return fmt.Errorf("total LLM concurrency must be greater than zero")
	}
	return validatePipelineProfiles(c.Pipelines, c.LLMProfiles)
}

func (c Config) LLMProfile(id string) (LLMProfile, bool) {
	trimmedID := strings.TrimSpace(id)
	for rawID, profile := range c.LLMProfiles {
		if strings.TrimSpace(rawID) == trimmedID {
			return profile, true
		}
	}
	return LLMProfile{}, false
}

func validateLLMProfiles(profiles map[string]LLMProfile) error {
	seen := make(map[string]struct{}, len(profiles))
	for rawID, profile := range profiles {
		id := strings.TrimSpace(rawID)
		if id == "" {
			return fmt.Errorf("LLM profile id must not be empty")
		}
		if _, ok := seen[id]; ok {
			return fmt.Errorf("LLM profile id %q is duplicated after trimming", id)
		}
		seen[id] = struct{}{}

		provider := strings.TrimSpace(profile.Provider)
		if provider != "" && provider != providerOpenAICompatible {
			return fmt.Errorf("LLM profile %q provider %q is not supported", id, provider)
		}
		if profile.TimeoutSeconds < 0 {
			return fmt.Errorf("LLM profile %q timeout seconds must not be negative", id)
		}
		if profile.MaxRetries < 0 {
			return fmt.Errorf("LLM profile %q max retries must not be negative", id)
		}
		if profile.MaxConcurrency < 0 {
			return fmt.Errorf("LLM profile %q max concurrency must not be negative", id)
		}
	}
	return nil
}

func validateDiagnostics(cfg DiagnosticsConfig) error {
	if strings.TrimSpace(cfg.WorkDir) == "" {
		return fmt.Errorf("diagnostics work dir must not be empty")
	}
	switch cfg.Retention {
	case "", diagnostics.RetentionAuto, diagnostics.RetentionAlways, diagnostics.RetentionNever:
		return nil
	default:
		return fmt.Errorf("diagnostics retention %q is not supported", cfg.Retention)
	}
}

func validatePipelineProfiles(profiles map[string]pipeline.PipelineProfile, llmProfiles map[string]LLMProfile) error {
	seen := make(map[string]struct{}, len(profiles))
	for rawID, profile := range profiles {
		id := strings.TrimSpace(rawID)
		if id == "" {
			return fmt.Errorf("pipeline id must not be empty")
		}
		if _, ok := seen[id]; ok {
			return fmt.Errorf("pipeline id %q is duplicated after trimming", id)
		}
		seen[id] = struct{}{}

		if profile.ID != "" && strings.TrimSpace(profile.ID) != id {
			return fmt.Errorf("pipeline %q profile id %q does not match map key", id, profile.ID)
		}
		if err := validateBindingLLMProfile(id, "", "input", profile.Input, llmProfiles); err != nil {
			return err
		}
		if err := validateBindingLLMProfile(id, "", "chunk", profile.Chunk, llmProfiles); err != nil {
			return err
		}
		if err := validateBindingLLMProfile(id, "", "output", profile.Output, llmProfiles); err != nil {
			return err
		}
		for rawLaneID, lane := range profile.Artifacts {
			laneID := strings.TrimSpace(rawLaneID)
			if laneID == "" {
				return fmt.Errorf("pipeline %q artifact lane id must not be empty", id)
			}
			if err := validateBindingLLMProfile(id, laneID, "extract", lane.Extract, llmProfiles); err != nil {
				return err
			}
			if err := validateBindingLLMProfile(id, laneID, "merge", lane.Merge, llmProfiles); err != nil {
				return err
			}
			if err := validateBindingLLMProfile(id, laneID, "normalize", lane.Normalize, llmProfiles); err != nil {
				return err
			}
			for i, validator := range lane.Validators {
				if err := validateBindingLLMProfile(id, laneID, fmt.Sprintf("validator[%d]", i), validator, llmProfiles); err != nil {
					return err
				}
			}
		}
	}
	return nil
}

func validateBindingLLMProfile(
	pipelineID string,
	laneID string,
	slot string,
	binding pipeline.ModuleBinding,
	profiles map[string]LLMProfile,
) error {
	profileID := strings.TrimSpace(binding.LLMProfile)
	if profileID == "" {
		profileID = pipeline.DefaultLLMProfile
	}
	if hasLLMProfile(profiles, profileID) {
		return nil
	}
	if laneID != "" {
		return fmt.Errorf("pipeline %q lane %q %s references unknown LLM profile %q", pipelineID, laneID, slot, profileID)
	}
	return fmt.Errorf("pipeline %q %s references unknown LLM profile %q", pipelineID, slot, profileID)
}

func hasLLMProfile(profiles map[string]LLMProfile, profileID string) bool {
	profileID = strings.TrimSpace(profileID)
	for rawID := range profiles {
		if strings.TrimSpace(rawID) == profileID {
			return true
		}
	}
	return false
}