Markdown and Mermaid Flowchart Master

你好，我是你的 Markdown 与 Mermaid 流程/架构图专家。将自然语言需求解析为规范化 Mermaid 代码，支持业务流程、时序图与系统架构的多层分解与着色规则，能自动拆分复杂逻辑为 L0/L1 图组，输出可直接嵌入文档或评审的代码块，请描述你的场景与关注点。

Diagram 1: [User Login Main Flow] ```mermaid %%{init: {"flowchart": {"defaultRenderer": "elk"}}}%% graph TD %% Core / Main flow (cool blue background + deep blue text) classDef main fill:#eff6ff,stroke:#3b82f6,color:#1e3a8a,stroke-width:2px %% Decision / Configuration nodes (soft orange background + brown-orange text) classDef check fill:#fff7ed,stroke:#f97316,color:#9a3412,stroke-width:2px %% Success / End nodes (eye-friendly green background + deep green text) classDef success fill:#f0fdf4,stroke:#22c55e,color:#14532d,stroke-width:2px %% Error / Exception nodes (alert red background + deep red text) classDef error fill:#fef2f2,stroke:#ef4444,color:#7f1d1d,stroke-width:2px %% General / External systems (muted gray background + charcoal text) classDef default fill:#f8fafc,stroke:#94a3b8,color:#334155,stroke-width:2px Start([User opens login page]) --> Input[Enter username and password] Input --> Request(Submit login request) Request --> Check{Are username and password correct?} Check -- No --> Fail[Display error and clear password field] Fail --> Input Check -- Yes --> Token[Generate Access Token] Token --> Cache[(Write to Redis cache)] Cache --> Success([Redirect to application homepage]) class Start,Input,Request,Token main; class Check check; class Cache default; class Fail error; class Success success; ```

Diagram 1: [System Architecture and Data Flow] ```mermaid %%{init: {"flowchart": {"defaultRenderer": "elk"}}}%% graph LR %% Core / Main flow (cool blue background + deep blue text) classDef main fill:#eff6ff,stroke:#3b82f6,color:#1e3a8a,stroke-width:2px %% Decision / Configuration nodes (soft orange background + brown-orange text) classDef check fill:#fff7ed,stroke:#f97316,color:#9a3412,stroke-width:2px %% Success / End nodes (eye-friendly green background + deep green text) classDef success fill:#f0fdf4,stroke:#22c55e,color:#14532d,stroke-width:2px %% Error / Exception nodes (alert red background + deep red text) classDef error fill:#fef2f2,stroke:#ef4444,color:#7f1d1d,stroke-width:2px %% General / External systems (muted gray background + charcoal text) classDef default fill:#f8fafc,stroke:#94a3b8,color:#334155,stroke-width:2px Client((Client)) -->|HTTP Request| APIGW((API Gateway)) APIGW -->|Forward| Auth[Auth Service] Auth -->|Validate and return token| UserSvc[(User Service)] UserSvc -->|Read/Write| DB[(User Database)] APIGW -.->|Dependency: Rate limiting / Circuit breaker| CircuitBreaker[(Circuit Breaker / Rate Limiter)] class Client,APIGW,Auth,UserSvc main; class DB default; class CircuitBreaker check; ```

Diagram 1: [L0 Main Flow - Download Engine Overview] ```mermaid %%{init: {"flowchart": {"defaultRenderer": "elk"}}}%% graph LR %% Core / Main flow (cool blue background + deep blue text) classDef main fill:#eff6ff,stroke:#3b82f6,color:#1e3a8a,stroke-width:2px %% Decision / Configuration nodes (soft orange background + brown-orange text) classDef check fill:#fff7ed,stroke:#f97316,color:#9a3412,stroke-width:2px %% Success / End nodes (eye-friendly green background + deep green text) classDef success fill:#f0fdf4,stroke:#22c55e,color:#14532d,stroke-width:2px %% Error / Exception nodes (alert red background + deep red text) classDef error fill:#fef2f2,stroke:#ef4444,color:#7f1d1d,stroke-width:2px %% General / External systems (muted gray background + charcoal text) classDef default fill:#f8fafc,stroke:#94a3b8,color:#334155,stroke-width:2px Start([Receive download request]) --> Validate[Configuration and permission validation] Validate --> Segmenter[Segmentation and scheduling] Segmenter --> Engine[Core download and retry engine] Engine --> Validator[Integrity validation (checksum/signature)] Validator -- Success --> Store[(Write to persistent storage)] Validator -- Failure --> ErrorHandler[Error handling and alerting] class Start,Validate,Segmenter,Engine,Validator main; class Store default; class ErrorHandler error; ``` Diagram 2: [L1 Sub-Flow - Core Download and Retry Engine] ```mermaid %%{init: {"flowchart": {"defaultRenderer": "elk"}}}%% flowchart TB %% Core / Main flow (cool blue background + deep blue text) classDef main fill:#eff6ff,stroke:#3b82f6,color:#1e3a8a,stroke-width:2px %% Decision / Configuration nodes (soft orange background + brown-orange text) classDef check fill:#fff7ed,stroke:#f97316,color:#9a3412,stroke-width:2px %% Success / End nodes (eye-friendly green background + deep green text) classDef success fill:#f0fdf4,stroke:#22c55e,color:#14532d,stroke-width:2px %% Error / Exception nodes (alert red background + deep red text) classDef error fill:#fef2f2,stroke:#ef4444,color:#7f1d1d,stroke-width:2px %% General / External systems (muted gray background + charcoal text) classDef default fill:#f8fafc,stroke:#94a3b8,color:#334155,stroke-width:2px StartPart([Receive segment task]) --> ForEach{Are there unfinished segments?} ForEach -- No --> Done([All segments completed]) ForEach -- Yes --> Fetch[(Request segment URL)] Fetch --> Download(Initiate HTTP download) Download --> CheckHTTP{Is HTTP status 2xx?} CheckHTTP -- No --> RetryBranch[Enter retry logic] CheckHTTP -- Yes --> WriteTemp[(Write to segment temporary file)] WriteTemp --> Checksum(Calculate checksum) Checksum --> Compare{Does checksum pass?} Compare -- Yes --> Merge([Merge segments and mark complete]) Compare -- No --> RetryBranch %% Retry logic details RetryBranch --> RetryCount{Retry count < limit?} RetryCount -- No --> MarkFail([Mark segment failed and report]) RetryCount -- Yes --> Backoff[Calculate backoff wait] Backoff --> Wait[(Wait: backoff duration)] Wait --> Download class StartPart,Fetch,Download,WriteTemp,Checksum,Merge main; class ForEach,CheckHTTP,Compare,RetryCount check; class Done,MarkFail success; class RetryBranch error; class Wait,Backoff default; ```